Fungal pathogen protection in potato by expression of a plant defensin peptide


Defensins are small cysteine-rich peptides with antimicrobial activity. We demonstrate that the alfalfa antifungal peptide (alfAFP) defensin isolated from seeds of Medicago sativa displays strong activity against the agronomically important fungal pathogen Verticillium dahliae. Expression of the alfAFP peptide in transgenic potato plants provides robust resistance in the greenhouse. Importantly, this resistance is maintained under field conditions. There have been no previous demonstrations of a single transgene imparting a disease resistance phenotype that is at least equivalent to those achieved through current practices using fumigants.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: alfAFP inhibits fungal growth in vitro.
Figure 2: Expression and localization of alfAFP in transgenic potato.
Figure 3: Greenhouse evaluation of alfAFP transgenic potato for resistance against V. dahliae.
Figure 4: Field evaluation of alfAFP transgenic potato for resistance against V. dahliae.
Figure 5: Evaluation of three alfAFP lines in field trials.
Figure 6: Phenotype of V. dahliae-infected transgenic and control potato plants.


  1. 1

    James, W.C., Teng, P.S. & Nutter, F.W. In CRC Handbook of pest management in agriculture , Edn. 2 (ed. Pimentel, D.) 15–50 (CRC Press, Ithaca, NY; 1990).

  2. 2

    Estruch, J.J. et al. Transgenic plants: an emerging approach to pest control. Nat. Biotechnol. 15, 137–141 (1997).

  3. 3

    Shah, D.M. Genetic engineering for fungal and bacterial diseases. Curr. Opin. Biotechnol . 8, 208–214 (1997).

  4. 4

    Jach, G. et al. Enhanced quantitative resistance against fungal disease by combinatorial expression of different barley antifungal proteins in transgenic tobacco. Plant J. 8, 97–109 ( 1995).

  5. 5

    Lorito, M. et al. Genes from mycoparasitic fungi as a source for improving plant resistance to fungal pathogens. Proc. Natl. Acad. Sci. U. S. A. 95, 7860–5. (1998).

  6. 6

    Epple, P., Apel, K. & Bohlmann, H. Overexpression of an endogenous thionin enhances resistance of Arabidopsis against Fusarium oxysporum. Plant Cell 9, 509–520 ( 1997).

  7. 7

    Hain, R. et al. Disease resistance results from foreign phytoalexin expression in a novel plant. Nature 361, 153– 156 (1993).

  8. 8

    Broekaert, W.F. et al. Antimicrobial peptides from plants. Crit. Rev. Plant Sci. 16, 297–323 ( 1997).

  9. 9

    Thevissen, K., Terras, F.R. & Broekaert, W.F. Permeabilization of fungal membranes by plant defensins inhibits fungal growth. Appl. Environ. Microbiol. 65 , 5451–5458 (1999).

  10. 10

    Barry, G. et al. Commercialization of glyphosate herbicide resistant crops for improved weed control. J. Cell. Biochem. 16 (Suppl. F), 202 (1992).

  11. 11

    McRae, K.B. & Platt, H.W. An index for cultivar resistance based on disease progress curves. Phytopathology 77, 1181–1186 (1987).

  12. 12

    Kaniewski, W. K. & Thomas, P.E. Field testing for virus resistance and agronomic performance in transgenic plants. Mol. Biotechnol. 12, 101–115 (1999).

  13. 13

    Information system for biotechnology.

  14. 14

    Garcia-Olmedo, F., Molina, A., Alamillo, J.M. & Rodriguez-Palenzuela, P. Plant defense peptides. Biopolymers 47, 479–491 (1998).

  15. 15

    Cornelissen B.J.C. et al. Fungal resistant plants, process for obtaining fungal resistant plants and recombinant polynucleotides for use therein. US 5,670,706 (1997).

  16. 16

    Liang, J., Shah, D.M., Wu, Y.S., Rosenberger, C.A. & Hakimi, S. Antifungal polypeptide(s) and methods for controlling plant pathogenic fungi. US 06121436 ( 2000).

  17. 17

    Sambrook, J., Fritsch, E. & Maniatis, T. Molecular cloning: a laboratory manual. (Cold Spring Harbor Laboratory, Cold Spring Harbor, NY; 1989).

  18. 18

    Hudyncia, J., Shew, H.D., Cody, B.R. & Cubeta, M.A. Evaluation of wounds as a factor to infection of cabbage by ascospores of Sclerotinia sclerotiorum. Plant Dis. 84, 316– 320 (2000).

  19. 19

    Long, D.H. Effect of nitrogen on disease progress of rice blast on susceptible and resistant cultivars. Plant Dis. 84, 403– 409 (2000).

  20. 20

    Anderson, N.A. & Hoyos, G.P. Evaluation of potato germplasm for Verticillium wilt resistance. Am. Potato J. 65, 469 (1988).

Download references


The authors wish to thank Doug Rouse (University of Wisconsin), Mary Powelson (Oregon State University), Jiamin Zeng, Kairong Tiang, Kim Rayford, Judy Heinz, Jerry Anderson, Karen Fitzsimmons, Bonnie Hsiang, Glenda DeBrecht, Tom Salaiz, Jim Zalewski, Stephanie Prinsen, and Marjorie A. Manning for their participation in various aspects of this work.

Author information

Correspondence to Jihong Liang.

Rights and permissions

Reprints and Permissions

About this article

Further reading